Problem: Simplify to lowest terms. $\dfrac{66}{55}$
Explanation: What is the greatest common factor (GCD) of 66 and 55? $66 = 2\cdot3\cdot11$ $55 = 5\cdot11$ $\mbox{GCD}(66, 55) = 11$ $\dfrac{66}{55} = \dfrac{6 \cdot 11}{ 5\cdot 11}$ $\hphantom{\dfrac{66}{55}} = \dfrac{6}{5} \cdot \dfrac{11}{11}$ $\hphantom{\dfrac{66}{55}} = \dfrac{6}{5} \cdot 1$ $\hphantom{\dfrac{66}{55}} = \dfrac{6}{5}$